It has been found that proline and derivatives thereof act as organocatalysts for organic synthesis. Particularly, proline and derivatives thereof have advantages in that an optically active proline skeleton is easily available, no metal is used, and their use environment is not limited. Proline and derivatives thereof exhibit catalytic activity for reactions useful for synthesis of raw materials of pharmaceuticals etc., such as a Michael reaction, a Diels-Alder reaction, and reactions including an aldol reaction and a Mannich reaction that proceed through an enamine mechanism, with high yield and high enantioselectivity (Non-Patent Literature 1). As for such proline derivatives, solid-phase catalysts using the proline derivatives are also known. For example, it has been proposed to obtain an asymmetric aldol reaction product in a batch process in the following manner (Non-Patent Literature 2). Resin particles obtained by suspension polymerization of a monomer composition containing an acrylate derivative monomer having a proline structure in its molecule, an unsaturated compound such as styrene or divinylbenzene, and a radical polymerization initiator are used as solid-phase asymmetric catalyst particles. The resin particles are charged into a reaction container charged with a solution in which a carbonyl compound having an α hydrogen is dissolved, and then the reaction solution mixture is heated while being mixed uniformly to thereby obtain the asymmetric aldol reaction product.